The biomedical and behavioral research community has long recognized the importance of chimpanzees (Pan troglodytes) as an animal model. Several measures have been instituted to stabilize populations, which are threatened in the wild. Most notably, Nations of the Convention on International Trade in Endangered Species (CITES) have specifically prohibited the importation of chimpanzees from the wild for research purposes;and the National Institutes of Health (NIH) created the `Chimpanzee Breeding and Research Program (CBRP). In 1986, the CBRP was created to insure a chimpanzee population in the United States for use in human health research. The University of Louisiana at Lafayette has been active in this endeavor since its conception. Chimpanzees continue to be essential models in the development of vaccines for hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis A virus (HAV), respiratory syncytial virus (RSV), and human immunodeficiency virus (HIV). In addition they play a critical role in the evaluation of thepharmacodynamics, pharmacokinetics, bioavailablity, safety, and efficacy of novel drug compounds, proteins and monoclonal antibodies. Specific aims of the application include the following: * To maintain capabilities to successfully breed (once the breeding moratorium has been lifted) and house chimpanzees in UL Lafayette-NIRC's CBRP AAALAC International-accredited colony * To conduct a longitudinal study to examine neurochemical and neuroendocrine correlates of aggressive and affiliative/social behavior and determine how position in the dominance hierarchy is associated with these parameters. * To collaborate and share data freely with the chimpanzee database grantees, investigators whose efforts would be supported by access to UL Lafayette's information and the ChiMP Coordinator, and to work with the ChiMP Advisory, Panel in developing long term plans for research use, breeding colony size, demographics, genetics, and long-term care. * To support national and international efforts to share biomedical research resources consistent with the National Institutes of Health's policy on Sharing of Model Organisms for Biomedical Research, and to enhance the development of and access to chimpanzee animal models critical to understanding human health needs consistent with NCRR's 2004-2008 Strategic Plan.